Resin shower tray deformation: causes, installation errors and solutions
A resin shower tray that bulges, lifts or loses its flatness after installation is naturally concerning. In most cases, the problem is not due to a manufacturing defect, but to unsuitable storage, an improperly prepared substrate or an overly rigid installation that prevents the shower tray from moving normally.
Installation that is too rigid or no perimeter clearance.
Flat, on a level and continuous surface.
Level, flat substrate, drainage test and flexible sealant.
The installation must follow the manufacturer’s recommendations.
Why can a resin shower tray deform?
A mineral resin shower tray is not a completely inert block. It is a technical composite material designed to withstand water, weight, temperature variations and everyday use. Like many materials, it may undergo slight expansion or contraction.
These movements are normal when anticipated. The problem occurs when the shower tray is constrained: overly rigid bonding, no perimeter joint, an uneven substrate, pressure against the walls or improper storage before installation.
Key takeaway
A shower tray does not deform spontaneously. It generally reacts to excessive stress or to an installation that does not leave enough room to accommodate the material’s natural variations.
Store the shower tray correctly before installation
Deformation can begin even before installation. A poorly stored shower tray may lose its flatness, especially if it remains for several days or weeks in an unsuitable position.
Upon delivery, the shower tray must be inspected and then stored flat on a clean, level and continuous surface. It must not be left leaning against a wall, placed on an edge or left on a transport pallet for an extended period.
- Inspect upon delivery: check the shower tray’s overall condition before storing it.
- Store it flat: the shower tray must rest on its entire surface, not just on a few points.
- Avoid vertical supports: a shower tray left leaning against a wall may bow over time.
- Protect it from the worksite: avoid impacts, heavy loads, dust and repeated foot traffic.
Common mistake
The pallet is for transport, not long-term storage. For a reliable installation, the shower tray must be stored in suitable conditions until installation.
Installation errors that cause deformation
In the vast majority of cases, a shower tray that bulges or lifts after installation is due to an installation error. The product is then subjected to mechanical stress and eventually deforms.
- Bonding the shower tray too rigidly: overly hard adhesive prevents the material’s natural movements.
- Using tile adhesive mortar: this type of product is too rigid for a mineral resin shower tray.
- Blocking the shower tray against the walls: without a perimeter gap, expansion cannot be absorbed.
- Installing it on an uneven support: pressure points can cause bulging over time.
- Forgetting the drainage test: an incorrect slope or a poorly positioned waste becomes very difficult to correct after bonding.
- Loading the shower tray during the work: unevenly distributed weight can create unnecessary stress before the shower is put into service.
Things to avoid at all costs
A resin shower tray should not be treated like a tile. An overly rigid installation can restrict the material and create stresses that eventually become visible on the surface.
How can you prevent a shower tray from deforming?
The correct method is to prepare a stable support, check the shower tray before permanently fixing it and use products compatible with the properties of the resin.
Check the support
The support must be clean, stable, dry and perfectly level. Any unevenness can create pressure points beneath the shower tray.
Perform a dry fit
Before bonding, position the shower tray without permanently fixing it to check its location, stability and alignment with the drainage outlet.
Test the drainage
Pour several litres of water before final installation. This test checks that the water drains correctly toward the waste.
Allow for a perimeter gap
A 2 to 3 mm gap around the shower tray allows it to absorb the material’s natural movements before the waterproof seal is applied.
The right approach
Use an elastic polyurethane sealant or a product recommended by the manufacturer. The aim is to hold the shower tray in place without rigidly restricting it.
Mineral resin: a reliable material when installed correctly
A quality mineral resin shower tray is designed to provide good stability, a comfortable surface and a modern finish. The material is appreciated for its ultra-flat appearance, pleasant feel and slip-resistant properties, depending on the model.
However, its reliability depends on following the storage and installation instructions. Like any composite material, it must be installed using a flexible, non-restrictive installation method.
Well-prepared support
A flat, continuous base limits stress beneath the shower tray and promotes good long-term stability.
Flexible installation
Proper fastening allows the material to absorb its micro-movements without creating excessive tension.
Peripheral seal
The sanitary seal ensures watertightness while allowing the shower tray the flexibility it needs to function properly.
What should you do if the shower tray is already deformed?
When a resin shower tray has been subjected to prolonged stress, the deformation may become permanent. This is known as plastic deformation: the material may not regain its original flatness, even after the stress is removed.
Minor deformation
A slight irregularity can sometimes be monitored or compensated for in the sealing, depending on the location and extent of the defect.
Significant deformation
If the shower tray is clearly lifting, obstructs drainage or compromises watertightness, replacement is often the only reliable solution.
Warning
Trying to force an already deformed shower tray flat again may increase the stresses. Before taking any action, the cause must be identified: storage, support, bonding, heat or lack of peripheral clearance.
Deformed shower tray: what does the warranty cover?
The warranty for a resin shower tray covers manufacturing defects found in a product that has been stored, handled and installed in accordance with the manufacturer's recommendations.
However, improper installation may result in exclusion from the warranty: rigid bonding, absence of a peripheral seal, uneven support, prolonged vertical storage, product modification or unplanned cutting.
- Product inspected upon delivery: the condition of the shower tray must be checked before installation.
- Proper storage: the shower tray must be stored flat before installation.
- Proper installation: the manufacturer's instructions must be followed.
- Suitable support: the floor must be level, stable and compatible with the selected shower tray.
SANIZÉO advice
Keep photos of the delivery, storage, dry fitting and drainage test. In case of doubt or dispute, these records help quickly identify the source of the problem.
Our mineral resin shower trays
A good shower tray should be selected according to the constraints of the installation: dimensions, drainage, support, finish, slip resistance and installation method. Here is a selection of mineral resin shower trays designed for long-lasting installation.
In summary: how can you prevent a resin shower tray from deforming?
A resin shower tray is reliable, durable, and comfortable when properly chosen, stored, and installed according to the manufacturer's recommendations.
- Choose a suitable shower tray: consider the dimensions, material, slip resistance, and compatibility with your installation.
- Store it flat: never vertically and never on an uneven surface.
- Prepare a level substrate: this is essential to prevent stress points.
- Dry-fit it first: check stability, the drain, and drainage before applying adhesive.
- Use a flexible sealant: avoid rigid adhesives and tile adhesive mortar.
- Leave peripheral clearance: 2 to 3 mm allows for natural movement.
The right shower tray + the right installation = fewer unpleasant surprises
If you are unsure about choosing a shower tray or its compatibility with your project, it is best to rely on proven products and appropriate advice before installation.
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